drivers/rtc/rtc-at91rm9200.c

   1 /*
   2  *      Real Time Clock interface for Linux on Atmel AT91RM9200
   3  *
   4  *      Copyright (C) 2002 Rick Bronson
   5  *
   6  *      Converted to RTC class model by Andrew Victor
   7  *
   8  *      Ported to Linux 2.6 by Steven Scholz
   9  *      Based on s3c2410-rtc.c Simtec Electronics
  10  *
  11  *      Based on sa1100-rtc.c by Nils Faerber
  12  *      Based on rtc.c by Paul Gortmaker
  13  *
  14  *      This program is free software; you can redistribute it and/or
  15  *      modify it under the terms of the GNU General Public License
  16  *      as published by the Free Software Foundation; either version
  17  *      2 of the License, or (at your option) any later version.
  18  *
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/time.h>
  25 #include <linux/rtc.h>
  26 #include <linux/bcd.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/ioctl.h>
  30 #include <linux/completion.h>
  31 #include <linux/io.h>
  32 #include <linux/of.h>
  33 #include <linux/of_device.h>
  34
  35 #include <asm/uaccess.h>
  36
  37 #include "rtc-at91rm9200.h"
  38
  39 #define at91_rtc_read(field) \
  40         __raw_readl(at91_rtc_regs + field)
  41 #define at91_rtc_write(field, val) \
  42         __raw_writel((val), at91_rtc_regs + field)
  43
  44 #define AT91_RTC_EPOCH          1900UL  /* just like arch/arm/common/rtctime.c */
  45
  46 struct at91_rtc_config {
  47         bool use_shadow_imr;
  48 };
  49
  50 static const struct at91_rtc_config *at91_rtc_config;
  51 static DECLARE_COMPLETION(at91_rtc_updated);
  52 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
  53 static void __iomem *at91_rtc_regs;
  54 static int irq;
  55 static DEFINE_SPINLOCK(at91_rtc_lock);
  56 static u32 at91_rtc_shadow_imr;
  57
  58 static void at91_rtc_write_ier(u32 mask)
  59 {
  60         unsigned long flags;
  61
  62         spin_lock_irqsave(&at91_rtc_lock, flags);
  63         at91_rtc_shadow_imr |= mask;
  64         at91_rtc_write(AT91_RTC_IER, mask);
  65         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  66 }
  67
  68 static void at91_rtc_write_idr(u32 mask)
  69 {
  70         unsigned long flags;
  71
  72         spin_lock_irqsave(&at91_rtc_lock, flags);
  73         at91_rtc_write(AT91_RTC_IDR, mask);
  74         /*
  75          * Register read back (of any RTC-register) needed to make sure
  76          * IDR-register write has reached the peripheral before updating
  77          * shadow mask.
  78          *
  79          * Note that there is still a possibility that the mask is updated
  80          * before interrupts have actually been disabled in hardware. The only
  81          * way to be certain would be to poll the IMR-register, which is is
  82          * the very register we are trying to emulate. The register read back
  83          * is a reasonable heuristic.
  84          */
  85         at91_rtc_read(AT91_RTC_SR);
  86         at91_rtc_shadow_imr &= ~mask;
  87         spin_unlock_irqrestore(&at91_rtc_lock, flags);
  88 }
  89
  90 static u32 at91_rtc_read_imr(void)
  91 {
  92         unsigned long flags;
  93         u32 mask;
  94
  95         if (at91_rtc_config->use_shadow_imr) {
  96                 spin_lock_irqsave(&at91_rtc_lock, flags);
  97                 mask = at91_rtc_shadow_imr;
  98                 spin_unlock_irqrestore(&at91_rtc_lock, flags);
  99         } else {
 100                 mask = at91_rtc_read(AT91_RTC_IMR);
 101         }
 102
 103         return mask;
 104 }
 105
 106 /*
 107  * Decode time/date into rtc_time structure
 108  */
 109 static void at91_rtc_decodetime(unsigned int timereg, unsigned int calreg,
 110                                 struct rtc_time *tm)
 111 {
 112         unsigned int time, date;
 113
 114         /* must read twice in case it changes */
 115         do {
 116                 time = at91_rtc_read(timereg);
 117                 date = at91_rtc_read(calreg);
 118         } while ((time != at91_rtc_read(timereg)) ||
 119                         (date != at91_rtc_read(calreg)));
 120
 121         tm->tm_sec  = bcd2bin((time & AT91_RTC_SEC) >> 0);
 122         tm->tm_min  = bcd2bin((time & AT91_RTC_MIN) >> 8);
 123         tm->tm_hour = bcd2bin((time & AT91_RTC_HOUR) >> 16);
 124
 125         /*
 126          * The Calendar Alarm register does not have a field for
 127          * the year - so these will return an invalid value.  When an
 128          * alarm is set, at91_alarm_year will store the current year.
 129          */
 130         tm->tm_year  = bcd2bin(date & AT91_RTC_CENT) * 100;     /* century */
 131         tm->tm_year += bcd2bin((date & AT91_RTC_YEAR) >> 8);    /* year */
 132
 133         tm->tm_wday = bcd2bin((date & AT91_RTC_DAY) >> 21) - 1; /* day of the week [0-6], Sunday=0 */
 134         tm->tm_mon  = bcd2bin((date & AT91_RTC_MONTH) >> 16) - 1;
 135         tm->tm_mday = bcd2bin((date & AT91_RTC_DATE) >> 24);
 136 }
 137
 138 /*
 139  * Read current time and date in RTC
 140  */
 141 static int at91_rtc_readtime(struct device *dev, struct rtc_time *tm)
 142 {
 143         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, tm);
 144         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 145         tm->tm_year = tm->tm_year - 1900;
 146
 147         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 148                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 149                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 150
 151         return 0;
 152 }
 153
 154 /*
 155  * Set current time and date in RTC
 156  */
 157 static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
 158 {
 159         unsigned long cr;
 160
 161         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 162                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 163                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 164
 165         /* Stop Time/Calendar from counting */
 166         cr = at91_rtc_read(AT91_RTC_CR);
 167         at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 168
 169         at91_rtc_write_ier(AT91_RTC_ACKUPD);
 170         wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
 171         at91_rtc_write_idr(AT91_RTC_ACKUPD);
 172
 173         at91_rtc_write(AT91_RTC_TIMR,
 174                           bin2bcd(tm->tm_sec) << 0
 175                         | bin2bcd(tm->tm_min) << 8
 176                         | bin2bcd(tm->tm_hour) << 16);
 177
 178         at91_rtc_write(AT91_RTC_CALR,
 179                           bin2bcd((tm->tm_year + 1900) / 100)   /* century */
 180                         | bin2bcd(tm->tm_year % 100) << 8       /* year */
 181                         | bin2bcd(tm->tm_mon + 1) << 16         /* tm_mon starts at zero */
 182                         | bin2bcd(tm->tm_wday + 1) << 21        /* day of the week [0-6], Sunday=0 */
 183                         | bin2bcd(tm->tm_mday) << 24);
 184
 185         /* Restart Time/Calendar */
 186         cr = at91_rtc_read(AT91_RTC_CR);
 187         at91_rtc_write(AT91_RTC_CR, cr & ~(AT91_RTC_UPDCAL | AT91_RTC_UPDTIM));
 188
 189         return 0;
 190 }
 191
 192 /*
 193  * Read alarm time and date in RTC
 194  */
 195 static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
 196 {
 197         struct rtc_time *tm = &alrm->time;
 198
 199         at91_rtc_decodetime(AT91_RTC_TIMALR, AT91_RTC_CALALR, tm);
 200         tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
 201         tm->tm_year = at91_alarm_year - 1900;
 202
 203         alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
 204                         ? 1 : 0;
 205
 206         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 207                 1900 + tm->tm_year, tm->tm_mon, tm->tm_mday,
 208                 tm->tm_hour, tm->tm_min, tm->tm_sec);
 209
 210         return 0;
 211 }
 212
 213 /*
 214  * Set alarm time and date in RTC
 215  */
 216 static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 217 {
 218         struct rtc_time tm;
 219
 220         at91_rtc_decodetime(AT91_RTC_TIMR, AT91_RTC_CALR, &tm);
 221
 222         at91_alarm_year = tm.tm_year;
 223
 224         tm.tm_hour = alrm->time.tm_hour;
 225         tm.tm_min = alrm->time.tm_min;
 226         tm.tm_sec = alrm->time.tm_sec;
 227
 228         at91_rtc_write_idr(AT91_RTC_ALARM);
 229         at91_rtc_write(AT91_RTC_TIMALR,
 230                   bin2bcd(tm.tm_sec) << 0
 231                 | bin2bcd(tm.tm_min) << 8
 232                 | bin2bcd(tm.tm_hour) << 16
 233                 | AT91_RTC_HOUREN | AT91_RTC_MINEN | AT91_RTC_SECEN);
 234         at91_rtc_write(AT91_RTC_CALALR,
 235                   bin2bcd(tm.tm_mon + 1) << 16          /* tm_mon starts at zero */
 236                 | bin2bcd(tm.tm_mday) << 24
 237                 | AT91_RTC_DATEEN | AT91_RTC_MTHEN);
 238
 239         if (alrm->enabled) {
 240                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 241                 at91_rtc_write_ier(AT91_RTC_ALARM);
 242         }
 243
 244         dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
 245                 at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour,
 246                 tm.tm_min, tm.tm_sec);
 247
 248         return 0;
 249 }
 250
 251 static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 252 {
 253         dev_dbg(dev, "%s(): cmd=%08x\n", __func__, enabled);
 254
 255         if (enabled) {
 256                 at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
 257                 at91_rtc_write_ier(AT91_RTC_ALARM);
 258         } else
 259                 at91_rtc_write_idr(AT91_RTC_ALARM);
 260
 261         return 0;
 262 }
 263 /*
 264  * Provide additional RTC information in /proc/driver/rtc
 265  */
 266 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 267 {
 268         unsigned long imr = at91_rtc_read_imr();
 269
 270         seq_printf(seq, "update_IRQ\t: %s\n",
 271                         (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
 272         seq_printf(seq, "periodic_IRQ\t: %s\n",
 273                         (imr & AT91_RTC_SECEV) ? "yes" : "no");
 274
 275         return 0;
 276 }
 277
 278 /*
 279  * IRQ handler for the RTC
 280  */
 281 static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 282 {
 283         struct platform_device *pdev = dev_id;
 284         struct rtc_device *rtc = platform_get_drvdata(pdev);
 285         unsigned int rtsr;
 286         unsigned long events = 0;
 287
 288         rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
 289         if (rtsr) {             /* this interrupt is shared!  Is it ours? */
 290                 if (rtsr & AT91_RTC_ALARM)
 291                         events |= (RTC_AF | RTC_IRQF);
 292                 if (rtsr & AT91_RTC_SECEV)
 293                         events |= (RTC_UF | RTC_IRQF);
 294                 if (rtsr & AT91_RTC_ACKUPD)
 295                         complete(&at91_rtc_updated);
 296
 297                 at91_rtc_write(AT91_RTC_SCCR, rtsr);    /* clear status reg */
 298
 299                 rtc_update_irq(rtc, 1, events);
 300
 301                 dev_dbg(&pdev->dev, "%s(): num=%ld, events=0x%02lx\n", __func__,
 302                         events >> 8, events & 0x000000FF);
 303
 304                 return IRQ_HANDLED;
 305         }
 306         return IRQ_NONE;                /* not handled */
 307 }
 308
 309 static const struct at91_rtc_config at91rm9200_config = {
 310 };
 311
 312 static const struct at91_rtc_config at91sam9x5_config = {
 313         .use_shadow_imr = true,
 314 };
 315
 316 #ifdef CONFIG_OF
 317 static const struct of_device_id at91_rtc_dt_ids[] = {
 318         {
 319                 .compatible = "atmel,at91rm9200-rtc",
 320                 .data = &at91rm9200_config,
 321         }, {
 322                 .compatible = "atmel,at91sam9x5-rtc",
 323                 .data = &at91sam9x5_config,
 324         }, {
 325                 /* sentinel */
 326         }
 327 };
 328 MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
 329 #endif
 330
 331 static const struct at91_rtc_config *
 332 at91_rtc_get_config(struct platform_device *pdev)
 333 {
 334         const struct of_device_id *match;
 335
 336         if (pdev->dev.of_node) {
 337                 match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
 338                 if (!match)
 339                         return NULL;
 340                 return (const struct at91_rtc_config *)match->data;
 341         }
 342
 343         return &at91rm9200_config;
 344 }
 345
 346 static const struct rtc_class_ops at91_rtc_ops = {
 347         .read_time      = at91_rtc_readtime,
 348         .set_time       = at91_rtc_settime,
 349         .read_alarm     = at91_rtc_readalarm,
 350         .set_alarm      = at91_rtc_setalarm,
 351         .proc           = at91_rtc_proc,
 352         .alarm_irq_enable = at91_rtc_alarm_irq_enable,
 353 };
 354
 355 /*
 356  * Initialize and install RTC driver
 357  */
 358 static int __init at91_rtc_probe(struct platform_device *pdev)
 359 {
 360         struct rtc_device *rtc;
 361         struct resource *regs;
 362         int ret = 0;
 363
 364         at91_rtc_config = at91_rtc_get_config(pdev);
 365         if (!at91_rtc_config)
 366                 return -ENODEV;
 367
 368         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 369         if (!regs) {
 370                 dev_err(&pdev->dev, "no mmio resource defined\n");
 371                 return -ENXIO;
 372         }
 373
 374         irq = platform_get_irq(pdev, 0);
 375         if (irq < 0) {
 376                 dev_err(&pdev->dev, "no irq resource defined\n");
 377                 return -ENXIO;
 378         }
 379
 380         at91_rtc_regs = ioremap(regs->start, resource_size(regs));
 381         if (!at91_rtc_regs) {
 382                 dev_err(&pdev->dev, "failed to map registers, aborting.\n");
 383                 return -ENOMEM;
 384         }
 385
 386         at91_rtc_write(AT91_RTC_CR, 0);
 387         at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 388
 389         /* Disable all interrupts */
 390         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 391                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 392                                         AT91_RTC_CALEV);
 393
 394         ret = request_irq(irq, at91_rtc_interrupt,
 395                                 IRQF_SHARED,
 396                                 "at91_rtc", pdev);
 397         if (ret) {
 398                 dev_err(&pdev->dev, "IRQ %d already in use.\n", irq);
 399                 goto err_unmap;
 400         }
 401
 402         /* cpu init code should really have flagged this device as
 403          * being wake-capable; if it didn't, do that here.
 404          */
 405         if (!device_can_wakeup(&pdev->dev))
 406                 device_init_wakeup(&pdev->dev, 1);
 407
 408         rtc = rtc_device_register(pdev->name, &pdev->dev,
 409                                 &at91_rtc_ops, THIS_MODULE);
 410         if (IS_ERR(rtc)) {
 411                 ret = PTR_ERR(rtc);
 412                 goto err_free_irq;
 413         }
 414         platform_set_drvdata(pdev, rtc);
 415
 416         dev_info(&pdev->dev, "AT91 Real Time Clock driver.\n");
 417         return 0;
 418
 419 err_free_irq:
 420         free_irq(irq, pdev);
 421 err_unmap:
 422         iounmap(at91_rtc_regs);
 423
 424         return ret;
 425 }
 426
 427 /*
 428  * Disable and remove the RTC driver
 429  */
 430 static int __exit at91_rtc_remove(struct platform_device *pdev)
 431 {
 432         struct rtc_device *rtc = platform_get_drvdata(pdev);
 433
 434         /* Disable all interrupts */
 435         at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
 436                                         AT91_RTC_SECEV | AT91_RTC_TIMEV |
 437                                         AT91_RTC_CALEV);
 438         free_irq(irq, pdev);
 439
 440         rtc_device_unregister(rtc);
 441         iounmap(at91_rtc_regs);
 442         platform_set_drvdata(pdev, NULL);
 443
 444         return 0;
 445 }
 446
 447 #ifdef CONFIG_PM_SLEEP
 448
 449 /* AT91RM9200 RTC Power management control */
 450
 451 static u32 at91_rtc_imr;
 452
 453 static int at91_rtc_suspend(struct device *dev)
 454 {
 455         /* this IRQ is shared with DBGU and other hardware which isn't
 456          * necessarily doing PM like we are...
 457          */
 458         at91_rtc_imr = at91_rtc_read_imr()
 459                         & (AT91_RTC_ALARM|AT91_RTC_SECEV);
 460         if (at91_rtc_imr) {
 461                 if (device_may_wakeup(dev))
 462                         enable_irq_wake(irq);
 463                 else
 464                         at91_rtc_write_idr(at91_rtc_imr);
 465         }
 466         return 0;
 467 }
 468
 469 static int at91_rtc_resume(struct device *dev)
 470 {
 471         if (at91_rtc_imr) {
 472                 if (device_may_wakeup(dev))
 473                         disable_irq_wake(irq);
 474                 else
 475                         at91_rtc_write_ier(at91_rtc_imr);
 476         }
 477         return 0;
 478 }
 479 #endif
 480
 481 static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
 482
 483 static struct platform_driver at91_rtc_driver = {
 484         .remove         = __exit_p(at91_rtc_remove),
 485         .driver         = {
 486                 .name   = "at91_rtc",
 487                 .owner  = THIS_MODULE,
 488                 .pm     = &at91_rtc_pm_ops,
 489                 .of_match_table = of_match_ptr(at91_rtc_dt_ids),
 490         },
 491 };
 492
 493 module_platform_driver_probe(at91_rtc_driver, at91_rtc_probe);
 494
 495 MODULE_AUTHOR("Rick Bronson");
 496 MODULE_DESCRIPTION("RTC driver for Atmel AT91RM9200");
 497 MODULE_LICENSE("GPL");
 498 MODULE_ALIAS("platform:at91_rtc");